The principles of Statistical Mechanics will be used to provide theoretical physical interpretations of the various structures that are important in living systems. These interpretations will be achieved in part by consideration of the formation of those structures, some of these processes of formation themselves representing important biological functions. Other static and dynamic properties of these structures will also be treated. Thus we shall consider liquid water and interpret its structure by study of its formation by vapor condensation. This should permit futher, more rigorous, treatment of hydrophobic bonding in such aqueous systems as lipid bilayers (in biomembranes) and nucleic acid and protein solutions. We shall especially consider gels of various sorts and their formation from the corresponding sols. Among the gelations to be studied are blood clotting and the formation of antigen-antibody complexes; biological gels such as cartilage will also be considered. Finally, time and funding permitting, we shall extend our experimental and theoretical investigation of dielectric relaxation in aqueous, DNA solutions. The principal method underlying our proposed research, that of interpreting the nature of a structure via statistical-mechanical investigation of the transition (gelation or condensation) in which it is formed from a simpler structure, is based on our recent discovery of the reason for the prior failure of the Flory-Stockmayer theory of the sol-gel transition to describe the gel phase and the analogous reason for the failure of the Mayer theory of vapor condensation to describe the liquid state - and also our recognition of how to correct this difficulty in both theories.